For many people who have lost their larynx due to cancer or other conditions requiring the removal of the larynx (i.e., “laryngectomee” patients), regaining speech is possible only through the use of an artificial larynx. The earliest artificial larynx dates back to around the 1920s, with electric versions appearing in the 1940s. These devices can make a huge difference in the lives of people who have had their voice boxes removed. Today, many regions provide such devices free of charge to patients, along with maintenance and training in how to use them.
One of the most common types of electrolarynxes is a hand-held device which is held against the throat and turned on when the person wants to speak, as shown, e.g., in FIG. 1, where an electrolarynx 100 is held against throat 20 of patient 10. The electrolarynx produces vibrations which are similar to those generated by the vocal cords, allowing the person to speak relatively normally. It is also possible to use an internal electrolarynx, which vibrates an inserted tube.
Learning to use an electrolarynx can take time. After surgery, patients often have scarring or other damage in their throats which may require them to move the electrolarynx around along their throat in order to find the best spot to use the device (sometimes referred to as a “sweet spot”). When well-positioned, the electrolarynx will allow people to speak relatively normally, although speech can have a slightly flattened, mechanical sound. Some people also find that the “sweet spot” changes with time, requiring small adjustments to the position of the device. Many patients like to use an external electrolarynx because it requires minimal maintenance, and if one device does not work, it is easy to replace it and work with another one.
In prior electrolarynxes, such as that shown in FIGS. 2A and 2B, a magnetic housing (typically embodied as a magnetic cup) is generally used in order to center the voice coil or coil wires. By centering the voice coil, a clear tone may be produced and amplified from the voice coil, which floats in the magnetic housing.
An issue with such prior art electrolarynxes is that these devices are turned on and off constantly, which results in wear and damage to the wires of the voice coil when the voice coil rubs against the magnetic housing while under the pull of gravity (hereinafter referred to as “gravitational wear”), such as when the device is left lying on its side (or along its axis) or when the device is held against the throat (e.g., as shown in FIG. 1) while in the off-state between sentences.
In addition, in prior art electrolarynxes, such as that shown in FIGS. 2A and 2B, the radial distance (i.e., extending from the T-axis) between the coil wires 140a and the inner diameter of magnetic cup 156 (denoted by distance “y” in FIG. 2A; hereinafter, “coil-cup gap” or “cup gap”) is less than the radial distance between the outer diameter of guide disc 144 and the inner diameter of coil cylinder 140b (denoted by distance “x”; hereinafter, “guide disc gap”). Such a configuration also contributes to gravitational wear of the coil wires.
In use, the coil wires produce an electromagnetic field driving a striker, which in turn perturbs a contact diaphragm so as to produce vibrations that simulate those generated by the vocal cords. Gravitational wear on the voice coils or coil wires may disrupt the electromagnetic field which diminishes or destroys the functionality of the electrolarynx, thus further diminishing the speech capabilities of the patients who have already lost their natural ability to speak.
The present invention is directed toward overcoming one or more of the problems discussed above.